.header {
    display: flex;
    justify-content: flex-start;
    align-items: flex-start;
    max-width: 880px;
    margin: 45px auto 40px;
    border-bottom: 1px solid rgba(84, 84, 84, 0.7);
}

@media screen and (max-width: 720px) {
    .header {
        margin: 28px auto 42px;
        max-width: 500px;
    }
}

@media screen and (max-width: 320px) {
    .header {
        max-width: 320px;
    }
}